Fluorochromes for detection of callose in meiocytes of olive (Olea europaea L.)

The callosic wall which covers microsporocyte mother cells during meiotic division has been studied using different fluorochromes as alternatives to the widely used aniline blue. We have confirmed that both acridine orange and 4', 6' diamidino-2-phenylindole (DAPI) produce a fluorescent response to callose which is comparable in specificity and intensity to that of aniline blue; therefore, they can be used to study callose wall formation. Staining properties of these fluorochromes, as well of those of curcumin and sirofluor, reported earlier as fluorescent stains for callose, are discussed. We also discuss the efficacy of the combined use of sirofluor and DAPI to study particular aspects of the deposition of callose.